1. Field Of The Invention
The present invention relates to machine and engine lubrication oil filters, and spin on type filters generally used on heavy duty equipment hydraulic systems, transmissions and the like.
It is well known that proper lubrication of machines and engines is perhaps the most critical routine step which can protect them from wear and greatly extend their useful life Lubricating oil, besides performing its lubricating and cooling functions in the engine, serves to remove acids and other impurities as well as wear residues. They are conventionally removed by filtering elements through which the lubricating oil is continuously circulated and by replacing the lubricating oil with new oil at frequent intervals during the utilization of the engine.
Experience has shown that the filtering elements do not always effectively remove fine metallic particles from the oil medium and that dilution of acids by the volume of the lubricating oil is insufficient to prevent noticeable corrosion of the metal in the engine which accelerates wear. In addition, the fine metallic particles accelerate the clogging of the filtering elements by all-embracing thereon and if they are dislodged from the paper filter element in agglomerated form, they tend to cause more engine damage than if they are uniformly disbursed throughout the volume of oil.
Various attempts have been made to incorporate magnetized particles in the filtering element or to place sheets of magnetized metal within the filter elements. Such approaches complicate the manufacture of the filtering elements and add greatly to the expense of replacing the filter element.
Other attempts have been made to incorporate magnetic means within the oil filter system by utilizing annular blocks at the base of the filter which have limited surface areas for contact with the circulating oil.
2. Prior Art
A vehicle oil filter is disclosed in U.S. Pat. No. 2,980,257 Paton wherein a circular block with a central aperture is provided in the lower portion of the filter casing. The block is formed of a composite of magnetic material and a mass of magnesium metal as an insert. The object is to both collect the ferrous metallic particles and to attempt to neutralize the action of sulfuric acid in the oil. The location at the base of the filter element is such that the oil briefly contacts the inserts, but the limited surface area and restricted position makes the device less than satisfactorily effective in performing its functions.
U.S. Pat. No. 3,279,607 Michaelson shows an oil filter cartridge wherein bars of magnetized material and bars of magnesium are placed in the folds of a corrugated filtering element in an attempt to remove metallic particles and neutralize sulfuric acid as in the Paton reference. The incorporation of the bars or plates within the folds of the filter element limits their effectiveness, particularly if they are not inserted in all of the folds. To do so however, would obviously greatly increase the cost and complexity of the manufacturing of the filter elements which are generally of a disposable nature and of nominal cost.
A magnetized helical coil to remove metallic particles from the oil is located externally of the filtering elements in U.S. Pat. No. 3,727,761 Aspenwall et al. in a complicated hydraulic filter structure.
Also of interest in U.S. Pat. No. 2,893,561 Duzich which discloses various sheet paper or batts of fibrous filter elements in which magnetized particles are diffusely located in order to attract metallic particles from the oil being filtered.
In U.S. Pat. No. 4,218,320 Liaw, an oil filter is disclosed in which an attached accessory wrap of either an electro-magnet or permanent magnet is wound around the main body of the filter in order to attract fine iron particles to it to prevent them from penetrating the rolled filter element. This device serves to lengthen the duration of the usefulness of the filter paper. It is would externally of the outer side of the filter can body and does not come in contact with the lubricating oil.
U.S. Pat. No. 3,342,339 Riolo disclosed a conventional casing structure with permanent magnets fixedly incorporated into the filter structure.
U.S. Pat. No. 2,795,333 Kennedy relates to a fuel filer and discloses a spring used to retain a treating element.
Additional prior references of interest are:
______________________________________ 1,602,935 10/1916 Rasey 2,690,842 10/1954 Spulvak 2,760,637 8/1956 Franch 2,983,384 5/1961 Winslow 3,072,260 1/1963 Szwargulski ______________________________________
My prior patent U.S. Pat. No. 4,501,660 provided a significant improvement over the devices of the foregoing references.
U.S. Pat. No. 4,501,660 discloses, in one embodiment, which in practical experience appears to be the preferred embodiment, an automotive lubricating oil filter device comprising a main container body having inlets and outlets for the lubricating oil to be filtered, and a cylindrical filtering element through which the oil is filtered from the outer portion of the body inwardly to a central cylindrical core. The core contains a magnesium metal helical structure within which is enclosed one or more longitudinal bars of magnetized metal.
The magnesium helical structure serves to neutralize sulfuric acid generated in the engine and the magnetized metal bars serve to remove fine metallic particles from the lubricating oil, preventing agglomoration on the filtering element, in addition to preventing engine wear. The structure comprising the helical magnesium metal and magnetized metal bars contained therein can be removed and cleaned to be regenerated without requiring disposal of the main filtering element or structure and vice versa.
The magnesium helix and magnetic bar structure combination utilized according to my patent U.S. Pat. No. 4,501,660 is sized for each size filter structure in which it is utilized in order to fit properly within the filter structure and so that the upper extended terminus of the helix does not extend too far into the engine or other structure to which it is secured when operatively joined to the input and output channels through which circulate the medium to be filtered.
The cost of manufacturing the magnesium helix and magnetized metal bar structure combination for use in various sized filters structure has been unnecessarily high because in general a different sized helix and bar structure was required for each different sized filter structure.
In addition, while the helix and bar structure of my prior patent could be regenerated by removing it from the filter structure and wiping the bars clean of metallic fines this was somewhat awkward because of the construction wherein the bars were totally surrounded by the helix. In practice it was also found that the metallic fines were attracted primarily only near the ends of the bar magnets and that much of the surface area of the magnetic bars did not collect fines.